1. Field of the Invention
The present invention relates to a liquid supply system supplying a liquid from a liquid supply source to an injection head, and an inkjet recording device including the same.
2. Description of the Related Art
Recently, relatively large printed items such as signboards, posters and the like are often printed by an inkjet recording device. Such a recording device consumes a larger amount of ink than a printer for home use, and therefore, adopts a structure in which a large capacity ink cartridge is located away from a carriage having an ink head mounted thereon, namely, an off-carriage system. In the case of a recording device of the off-carriage system, an ink supply path (preferably, flexible tube) between the ink cartridge and the ink head becomes longer as the recording device increases in size. This increases the pressure fluctuation in the ink supply path. As a result, ink is not supplied to the ink head stably, which may decrease the printing quality.
In such a situation, for example, Japanese Laid-Open Patent Publication No. 2010-194915 discloses an inkjet printer including a damper and a tube pump located on an ink supply path. With this structure, the pressure fluctuation is alleviated by the damper and thus the ink is supplied to the ink head stably.
In a recording device of the off-carriage system, the ink cartridge may be located at a position higher than that of the ink head. In this case, the hydraulic head of the ink cartridge is higher than that of the ink head. This causes an undesirable possibility that the ink may leak from the ink head while printing is not performed. With the structure described in Patent Japanese Laid-Open Patent Publication No. 2010-194915, the tube pump is at a stop while the printing is not performed. Therefore, it is considered that the ink supply path (tube) in the tube pump is pressed to be closed, and thus the ink is prevented from leaking from the ink head.
However, with the above-described structure, in the case where, for example, the printer is not used for a long time, the tube is kept on pressed at the same position, namely, such a position of the tube is kept crushed. In this case, the tube may be softened at this position and the elasticity thereof may be decreased. As a result, the ink flow path may be occluded or broken, and thus it may become difficult to supply the ink stably for the printing.